An actuator of the type in question, by means of which a locking unit known from WO 2012/152361 A1 can be unlocked, for example, is known from WO 2012/104207 A1.
Locking units are encountered in many forms in vehicle seats. The essential task of known locking units is to be able to produce different seating configurations of the vehicle seat (e.g. the folding over of a rear seat backrest to increase the luggage space) or to enable convenient adjustment of the vehicle seat (driver seat and/or rear seats). Both tasks are performed by different categories of locking unit.
The first category of locking unit comprises fixed point locking systems. These are distinguished by the fact that the locking unit locks only in one position of the seat and/or of the backrest and hence fixes the seat and/or the backrest relative to an adjacent component, generally relative to the vehicle. These locking units, e.g. rotary latch locks, are sometimes referred to as locks or latches and are typically used with folding backrests to increase the luggage space. To a very large extent, the locking unit is positioned in the backrest. Other applications are systems for locking removable seats to the vehicle floor and also locking systems within a seat in the case of flexible seating systems.
The second category of locking unit differs from the first category in that the locking units can be locked in different positions. It is thus possible to adjust components of the seat relative to the seat itself and/or to the vehicle in accordance with the stipulations of a customer. This category is typically used to adjust the inclination of the backrest. In some cases, these locking units are also developed to enable a rear seat bench system to be folded over. These locking units, e.g. latching fitments, are sometimes also referred to as levers.
Actuation of the locking units is very largely accomplished by hand (manual actuation). Depending on the installation space situation and requirements, an actuating unit for the locking unit can be spatially separated from the locking unit. In this case, the force is generally transmitted from the actuating unit to the locking unit by a Bowden cable. Thus, the user of the seat gives the signal and simultaneously supplies the necessary force to unlock the locking unit. Sometimes, and especially when using Bowden cables, there can be a considerable rise in the actuating force.
To improve convenience, electric actuation is used as well as manual actuation. In these cases, only the trigger command is given by a user. The necessary force is then produced by an actuator, which consequently opens the locking unit.
The different requirements made on the actuators in this context—both by the vehicle and by the user of the seat—cannot be satisfied by the actuators known from the prior art. To provide additional functions, e.g. position detection, status interrogation, communication or separation between the signal and the power, additional sensors, indicator elements and/or external control units are employed.
However, these are associated with disadvantages since it is often impossible to install a control unit close to the actuators, as a result of which certain functionalities, e.g. control of the actuators by pulse width modulation (PWM for short) can be achieved only at considerable expense. Moreover, additional sensors must be employed to produce complex information for the user. Thus, an additional angle transmitter must be installed to cancel unlocking again once the backrest has been completely folded over and needs to be locked in this position.
An actuator which has a corresponding control unit is described in WO 2012/104027 A1. This actuator has the capacity for electric forward and reverse adjustment depending on the position of the actuating element in the actuator, which is sensed in the respective end positions. Automatic electric return is thereby possible, making it possible to eliminate the return spring.